Michael Zemlin

Mechanisms That Shape Human Antibody Repertoire Development in Mice Transgenic for Human Ig H and L Chain Loci

To determine the impact of the milieu on the development of the human B cell repertoire, we carried out a comprehensive analysis of productive and nonproductive Ig gene rearrangements from transgenic mice engineered to express single copies of the unrearranged human H chain and L chain Ig gene loci. By examining the nonproductive repertoire as an indication of the immediate product of the rearrangement machinery without an impact of selection, we discovered that the distribution of human rearrangements arising in the mouse was generally comparable to that seen in humans. However, differences between the distribution of nonproductive and productive rearrangements that reflect the impact of selection suggested species-specific selection played a role in shaping the respective repertoires. Although expression of some VH genes was similar in mouse and human (IGHV3-23, IGHV3-30, and IGHV4-59), other genes behaved differently (IGHV3-33, IGHV3-48, IGHV4-31, IGHV4-34, and IGHV1-18). Gene selection differences were also noted in L chains. Notably, nonproductive human VH rearrangements in the transgenic mice expressed shorter CDRH3 with less N addition. Even the CDRH3s in the productive rearrangements were shorter in length than those of the normal human productive repertoire. Amino acids in the CDRH3s in both species showed positive selection of tyrosines and glycines, and negative selection of leucines. The data indicate that the environment in which B cells develop can affect the expressed Ig repertoire by exerting influences on the distribution of expressed VH and VL genes and by influencing the amino acid composition of the Ag binding site.

Ante-, peri- and postnatal factors associated with intraventricular hemorrhage in very premature infants

BACKGROUND Intraventricular hemorrhage (IVH) is one of the most serious complications in preterm infants and is associated with neurological sequelae and mortality. Over the past few decades, the rate of IVH has decreased due to improved neonatal intensive care. However, up to 15-25% of very and extremely premature infants (<32 and <28weeks of pregnancy (WOP) respectively) still suffer from IVH. STUDY PURPOSE The aim of this study was to perform an updated, multicenter analysis to identify ante-, peri, and postnatal factors other than gestational age/birth weight associated with IVH of any grade in a large cohort of very and extremely premature infants. METHODS We performed a retrospective analysis in a prospectively conducted multicenter cohort study between 01/01/1998-31/12/2012 at 5 level 3 perinatal centers. All relevant ante-, peri- and neonatal data were collected and univariate as well as multivariate logistic regression analysis was performed. RESULTS 765 inborn infants with a gestational age<32 WOP were enrolled into this study (369 (48.2%) female; 396 (51.8%) male). Birth weight ranged from 315g to 2200g (mean 1149.7g, SD 371.9g); 279 (36.5%) were born ≤27+6 WOP and 486 (63.5%)≥28+0 WOP. IVH was seen in 177 (23.1%) patients. Multivariate analysis revealed that in addition to higher gestational age (OR 0.7, CI [0.6-0.8]), antenatal steroid treatment (OR 0.3, CI [0.2-0.6]) and caesarian section without uterine contraction (OR 0.6, CI [0.4-0.9]) were associated with a lower rate of IVH while RDS (OR 5.6, CI [1.3-24.2]), pneumothorax (OR 2.8, CI [1.4-5.5]) and use of catecholamines (OR 2.7, CI [1.7-4.5]) were associated with an increased risk of IVH. After exclusion of gestational age and birth weight from multivariate analysis, early onset sepsis (OR 1.6, CI [1.01-2.7]) and patent ductus arteriosus (OR 1.9, CI [1.1-3.1]) were associated with a higher rate of IVH. In addition, univariate analysis revealed that Apgar scores at 5min (p<0.001), BDP/ROP/NEC (p<0.001), mechanical ventilation (p<0.001) and inhalative nitric oxide (p<0.001) were significantly associated with IVH. CONCLUSIONS Our comprehensive analysis demonstrated that the occurrence of IVH in very premature infants is significantly associated with ante-, peri- and postnatal factors being either related to the degree of immaturity or indicating a critical clinical course after birth. The analysis reiterates the necessity for a very close cooperation between obstetricians and neonatologists to reduce the incidence of IVH in this susceptible cohort.

Preterm Birth Affects the Risk of Developing Immune-Mediated Diseases

Prematurity affects approximately 10% of all children, resulting in drastically altered antigen exposure due to premature confrontation with microbes, nutritional antigens, and other environmental factors. During the last trimester of pregnancy, the fetal immune system adapts to tolerate maternal and self-antigens, while also preparing for postnatal immune defense by acquiring passive immunity from the mother. Since the perinatal period is regarded as the most important “window of opportunity” for imprinting metabolism and immunity, preterm birth may have long-term consequences for the development of immune-mediated diseases. Intriguingly, preterm neonates appear to develop bronchial asthma more frequently, but atopic dermatitis less frequently in comparison to term neonates. The longitudinal study of preterm neonates could offer important insights into the process of imprinting for immune-mediated diseases. On the one hand, preterm birth may interrupt influences of the intrauterine environment on the fetus that increase or decrease the risk of later immune disease (e.g., maternal antibodies and placenta-derived factors), whereas on the other hand, it may lead to the premature exposure to protective or harmful extrauterine factors such as microbiota and nutritional antigen. Solving this puzzle may help unravel new preventive and therapeutic approaches for immune diseases.

Serum titers of autoantibodies against α-synuclein and tau in child- and adulthood

Autoreactive antibodies against the proteins alpha-synuclein (α-syn) and tau are detectable in body fluids of both healthy and diseased elderly people. However, nothing is known about their presence or titers in children. To close this gap and to characterize their temporary expression levels, we used ELISA techniques to investigate the serum titers of α-syn and tau reactive autoantibodies in 37 and 32 adults and 37 and 31 children, respectively. Most serum samples from the children exhibited both antibody types and interestingly, the levels were similar to those observed in the adult serum samples. Furthermore, sex-specific analysis revealed significantly increased α-syn reactive autoantibody titers in female children. The presence of α-syn and tau reactive autoantibodies in early childhood indicates that both immunoglobulins belong to the pool of naturally occurring autoantibodies (nAbs), as their antigen-independent synthesis from birth is a crucial characteristic. Due to their general participation in the maintenance of the physiological homeostasis, we hypothesize that both investigated nAbs are involved in the metabolic regulation of their specific antigen. Therefore, they may be a part of a mechanism that already exists in the innate immunological repertoire to provide protection from pathologies caused by dysregulated α-syn and tau metabolisms.

Optimized care in Patients with Rare Diseases: TSC at the Center for Rare Diseases (ZSEUKS) at Saarland University Medical Center, Germany

Providing comprehensive medical care for patients with rare diseases is both challenging and rewarding. We will give a short summary of the most relevant medical issues pertinent to this subject, and will illustrate some of these issues by sharing our experience in the care of patients with TSC disease.

Reference values for nucleated red blood cells and serum lactate in very and extremely low birth weight infants in the first week of life

STUDY PURPOSE To provide reference values for nucleated red blood cells and serum lactate concentrations in very and extremely low birth weight (VLBW/ELBW) infants in the first week of life. PATIENTS AND METHODS Retrospective data analysis of serial, daily measurements of NRBC counts and serum lactate during the first 6days of life in VLBW and ELBW infants. RESULTS In total, 250 infants<1500g were included in this study. Intrauterine growth retardation (IUGR) was seen in 87 (34.8%) patients. Gestational age (GA) ranged from 23 to 35weeks (mean 29.0weeks) and birth weight (BW) was 320-1499g (mean 1047.9g). During hospital stay, 55 (22%) patients developed IVH and 55 children (22%) BPD. PVL was seen in 12 (4.8%) cases, ROP in 93 (37.2%) and NEC in only 1 (0.4%) patient. NRBC counts as well as serum lactate concentrations depended significantly on birth weight (p<0.01) and presence respectively absence of IUGR (p<0.01). Both NRBC counts and serum lactate concentrations declined constantly during the 6-day period (p<0.01), and both were highly inter-correlated (p<0.01). CONCLUSIONS This is one of only a very few studies that systematically and serially evaluated both NRBC counts and serum lactate concentration in VLBW and ELBW infants in the first 6days of life. Both parameters were significantly dependent on birth weight and the presence of IUGR. Moreover, a significant correlation between NRBC counts and serum lactate concentrations in this early period of life could be demonstrated. In future studies, the role of these readily available biomarkers in predicting important neonatal outcome parameters needs to be evaluated in a prospective manner.

Diagnosis and Treatment of Tuberous Sclerosis Manifestations in Children: A Multicenter Study

Abstract Tuberous sclerosis complex (TSC) is a genetic disease with a significant morbidity and mortality. We conducted a retrospective analysis of two cohorts (Vall d’Hebron University Hospital [HVH], Barcelona, Spain, 1982‐2015, and at Saarland University Medical Center [UKS], Homburg, Germany, 1998‐2015) to assess prevalence and treatment of TSC associated manifestations and to evaluate if the follow‐up was in line with published recommendations. This was considered if more than 15% of patients did not receive adequate examination with regard to potential organ involvement. A definite diagnosis was made in 52 patients (96%), and a possible diagnosis was made in 2 patients (4%). Thirty‐four (63%) patients were from HVH and 20 (37%) from UKS. Median age at first presentation was 6 months (interquartile range: 0‐38 months), and median time of follow‐up was 6 years (interquartile range: 2‐13 years). Clinical symptoms that led to a diagnosis of TSC were cardiac rhabdomyoma (22/54), epilepsy (20/54), and cutaneous manifestations (4/54). Assessment of neuropsychiatric, renal, and ocular manifestations was inadequate in both hospitals, whereas cutaneous manifestation was inadequate at UKS only. Our data demonstrate insufficient examinations in a substantial number of TSC patients with regard to neuropsychiatric, renal, ocular, and cutaneous manifestations. The recently published guidelines may prove valuable in establishing a more comprehensive approach.

A Neonate with an Unusual Midline Defect and Cardiovascular Anomaly

We present a female neonate with a sternal cleft (SC) and additional aortic aneurysm who presented with respiratory failure. Stabilization of the SC was achieved by using the xyphoid process as an autologous graft bridging the upper part of the SC. We conclude that a step-wise correction of the SC with the use of an autologous graft may improve respiratory function, and should be considered when complete surgical correction is not feasible.